The foam and wax material in both hard and soft states.
Anette Hosoi/MIT

Octopuses have it easy when it comes to fitting through small spaces. With no skeletons, they can squish their way through all sorts of little openings. Robots, however, can't just ooze their way through crevices. Typical robot skeletons made of metal or plastic aren't very forgiving, but a new material formed of foam and wax could make robots more like octopuses.

The phase-changing material can switch between hard and soft states. Robots built with the material could conceivably be used for surgical applications where they need to navigate inside the human body or for disaster recovery efforts where they may need to squeeze through a hole and then harden on the other side to explore an area or move debris.

The material is made from foam coated in wax that can be formed into a lattice-like structure to act as a robot's body. Heating the coating makes the wax pliable, turning the material soft. In a robot, this could be achieved by running a wire that carries an electric current to generate heat on demand. Besides turning a rigid robot into a squishy one, it could also be used to repair a bot's infrastructure.

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"This material is self-healing," said Anette Hosoi, professor of mechanical engineering and applied mathematics at MIT and one of the creators of the material. "So if you push it too far and fracture the coating, you can heat it and then cool it, and the structure returns to its original configuration."

The basic material components, wax and polyurethane foam, are pretty low-tech. Hosoi said they could be picked up a craft store, which opens up the possibility of using it for very low-cost robots. The researchers also created a 3D-printed version of the foam lattice, which allows for greater control over the structure of the material.

Robots have been branching out from the typical hard-metal types we're all used to. Other MIT researchers built a robot fish recently, while scientists back in 2012 revealed a pillowy robotic jellyfish. These "soft" robots can be gentle on people that interact with them and can pull off maneuvers that may be difficult for their more rigid robotic cousins.

About the author

Freelance writer Amanda C. Kooser covers gadgets and tech news with a twist for CNET's Crave blog. When not wallowing in weird gadgets and iPad apps for cats, she can be found tinkering with her 1956 DeSoto.
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